Fragment in FrameLayout not showing in CoordinatorLayout

Question

I opened the default Android Studio App with a NavigationDrawer. The default content-view is not very useful, therefore I tried to replace it with a FrameLayout so I can add Fragments.

If I just replace content_main with the FrameLayout the Fragment will not be shown at all.

If I pull out the FrameLayout out of app_bar_main.xml into activity_main.xml it is shown but it overlaps with the Toolbar.

MainActivity.java

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //FloatingActionButton

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.addDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);

        FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction()
                .add(R.id.content_frame, new Fragment1())
                .commit();
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/drawer_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:openDrawer="start">

    <include
        layout="@layout/app_bar_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <android.support.design.widget.NavigationView
        android:id="@+id/nav_view"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        android:fitsSystemWindows="true"
        app:headerLayout="@layout/nav_header_main"
        app:menu="@menu/activity_main_drawer" />

</android.support.v4.widget.DrawerLayout>

app_bar_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="org.altoware.weity.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <FrameLayout
        android:id="@+id/content_frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@drawable/ic_menu_share" />

</android.support.design.widget.CoordinatorLayout>

Answer 1

You need to set a layout behaviour on the FrameLayout to make it work in a CoordinatorLayout.

app:layout_behavior="@string/appbar_scrolling_view_behavior"

Answer 2

In my case in was the android.support.v4.widget.NestedScrollView that was preventing fragment replacement transaction. I replaced NestedScrollView with LinearLayout which had app:layout_behavior="@string/appbar_scrolling_view_behavior" and fragment started working.

 <LinearLayout
            android:orientation="vertical"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_behavior="@string/appbar_scrolling_view_behavior"
            android:background="@color/activityBackground">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="title"/>

            <fragment
                android:name="com.stxnext.stxinsider.DetailsActivity$EmptyFragment"
                android:id="@+id/activity_details_content_fragment"
                android:layout_width="match_parent"
                android:layout_height="match_parent" />

  </LinearLayout>

Activity:

    val detailsContentFragment = DetailsListFragment()

    val transaction = fragmentManager.beginTransaction()
    transaction.replace(R.id.activity_details_content_fragment, detailsContentFragment)
    transaction.addToBackStack(null)
    transaction.commit()